


Gone Today, Heir Tomorrow

by DarkestElemental616



Category: Avatar: The Last Airbender, Kingdom Hearts
Genre: Alternate Universe - Avatar & Benders Setting, Alternate Universe - Fusion, Gen, Roxas gets screwed over in every reality
Language: English
Status: In-Progress
Published: 2017-08-29
Updated: 2017-10-29
Packaged: 2018-12-21 05:25:35
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 2,859
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11937243
Author URL: https://archiveofourown.org/users/DarkestElemental616/pseuds/DarkestElemental616
Summary: The Avatar is invisible. Or, Roxas is the worst Avatar ever.





	1. Chapter One

The Avatar was invisible. One would think they wouldn’t be— _couldn’t_ be—given that they were the only human alive who could bend multiple elements, but the truth was that people are often so blinded by what they expect to see that the obvious signs pass them by.

Then again, what kind of Avatar couldn’t see spirits, much less speak with them? What kind of Avatar was almost hilariously inept with animals, when every Avatar before always had some kind of animal guide? What kind of Avatar was a late bloomer? Not even the ‘wasn’t able to bend their second element until the age of ten’ kind of late bloomer, but the kind of late bloomer who couldn’t even pass as a bender in the first place until puberty.

Those were the questions Roxas often asked himself. His twin brother, Sora, had been able to see spirits since they were both only two, and made friends with every single animal, human, and spirit he met.

What kind of an Avatar could be so easily overshadowed?

Still, the monks at the Southern Air Temple were always kind to him. Even before Roxas had been actually airbending, they had allowed the twins to train with the other Air Acolytes and each other—if only because Sora refused to be apart from Roxas for more than a few minutes at a time. When Roxas finally _did_ airbend, he could at least catch up with the others quickly, and Sora knew exactly where his twin might need help. Thus they both finished their training and earned their tattoos, and the day they turned sixteen, Monk Xaldin took Sora aside (and Roxas, once Sora very loudly insisted that whatever they had to tell him they could tell them _both_ ) to tell the Avatar of his identity and his destiny.

Roxas found the entire situation both horrible and ironically hilarious. He’d accidentally set himself on fire three months before in a fit of frustration, and Sora had ended up shoving him into the courtyard fountain to put him out. Sora had never even shown the slightest inkling of bending anything but air. But because no one had been around for that incident, and because Sora was older by a scant hour and could actually act like what everyone thought an Avatar should be, it was Sora they were proposing to send to the Southern Water Tribe to learn waterbending.

Sora, as always led by wanderlust, easily agreed…until Xaldin said that it would be inappropriate for Roxas to come with him.

“What do you _mean_ Roxas has to stay here?!”

Sora’s voice carried easily through the hallways, drowning out the constant background echo of chatter and prayer. Roxas winced.

“I can’t just leave him behind!” Sora continued, crossing his arms in front of his chest. “Where I go, Roxas goes!”

“Young Avatar,” Xaldin failed to notice the way Roxas’ lips thinned and the way Sora’s stubborn stance widened. “It isn’t done. The Avatar is the only one who needs to know all four bending styles. For an airbender to learn anything else is unnecessary.”

Sora stood his ground, blue eyes narrowed. “Either he goes with me, or I don’t go at all,” he insisted.

“I want to go,” Roxas said at the same time. Even a secondhand education was better than nothing, since he was nowhere near summoning any of the other elements at will yet. He wilted a little as Xaldin turned a glare in his direction before his spine stiffened in anger. “I mean, learning other bending styles is a good idea sometimes. Redirecting lightning isn’t a firebender technique; it’s based on waterbending. But firebenders can still use it. And firebenders and earthbenders both have the potential to bend lava, right?” He was desperate now, hoping to make a crack in Xaldin’s disapproval before his chance was gone forever. “Besides, then Sora will have someone he’ll actually practice with! And…”

“And then I can actually focus,” Sora continued quickly. “Otherwise I’d miss him too much to focus on, uh…being the Avatar and stuff. And no one knows more about spirits besides airbenders than the Southern Water Tribe. Airbenders need to learn more about spirits because we can see them better, so…so it’ll be good for Roxas to get a different perspective and maybe he’ll get better at seeing them and at astral projection and stuff.”

“We can’t—”

“It’d be like leaving half of me behind.” Sora gave Xaldin his best puppy eyes. “Please? The training will be _awful_ without Roxas there.”

There was a long, painful silence. Roxas could see Sora’s bright expression falter out of the corner of his eye, but he was more focused on staring Xaldin down. One way or another, he was going to the South Pole.

Finally, Xaldin sighed in frustration. “All right. Pack your bags, you two. We leave at sunrise.”

Sora’s whoop of joy could be heard halfway down the mountain.


	2. Chapter Two

**Summary for the Chapter:**

> On their way to the South Pole, the Avatar gets a dire warning...

Roxas did not like boats, he decided. Even the fast, engine-driven ones bounced on the water, and Xigbar had decided that there was no need for them to take the short way to the South Pole. Therefore, he had spent the last two weeks in absolute misery.

“Why do we even have to do the water tribes first?” he muttered from his hammock, looking green. “I wanted to master fire first.”

Sora turned away from the porthole with a shrug. “Tradition, I guess? Water _does_ come right after air in the cycle, and you know how Master Xigbar is about tradition. Besides, water and air are supposed to be easy to learn once you already know one of them, because of the whole, uh…” His nose wrinkled in thought for a moment before he continued, “the whole flowing thing.”

Roxas snorted at that, and Sora couldn’t help but laugh in response. Roxas had always proved to be _terrible_ at ‘the whole flowing thing’. It had taken ages for him to get the flow of _air_.

“Aww, c’mon, Roxas. It’ll be fun!” Sora said brightly, clapping Roxas on the shoulder. “We get to play in the snow! And _with_ the snow! I mean, at least you’ll get to do that part.”

“I hate you.” Roxas rolled over, turning his back on Sora. “I hate my whole life.”

His breathing slowly evened out into sleep as Sora sat by the bed, playing with small puffs of air to entertain himself. The sea was calm and rocked the ship, and the hammock, gently. Finally, Sora padded over to join Roxas, wrapping his thin arms around his twin.

“It’s gonna be okay, Roxas,” Sora whispered as the younger boy groaned and snuggled into his warmth. “I’m here, and I’m always gonna be here to protect you. _Nothing_ is going to hurt you. I promise.”

\------------

By the time Roxas woke up, the sun had set. He couldn’t help but feel relief, though, knowing the trip was almost over. Only another week or so at sea and they’d be back on solid ground again.

“Sora?” Roxas wriggled a little in Sora’s grip. His twin had ended up wrapping himself completely around Roxas in the last few hours, effectively pinning them both into the hammock. “Soraaaa. Lemme go.”

“Idunwanna,” Sora mumbled, tightening his grip. He was still fast asleep.

“C’mon, Sora…”

The only response he got was a soft snore.

Roxas huffed. All right. He’d have to do it the hard way, then.

Slowly, carefully, he pried Sora off of him, stuffing their pillow and blankets in his place as he went so Sora wouldn’t immediately notice his absence. Then he rolled off the hammock onto the deck, grabbed his glider, and headed for the door. Roxas had spent the entirety of this ship seasick and below deck; he was starting to stifle. He needed some fresh air.

The young monk silently slipped out into the corridor, hand trailing along the smooth wooden wall to keep his balance. Somewhere around here was a way to the upper deck, and the sky.

The cold salty air practically punched him in the face when he finally emerged, knocking him breathless. It was refreshing, actually, after all those weeks, and the stars were duller than they had been at the Air Temple but still gleamed invitingly. Stepping carefully across the deck, Roxas could feel the wind tugging at his clothes, as if begging him to join it.

“Well, that’s what I came up here for,” Roxas said under his breath, enjoying the way the wind ruffled at his slow-growing hair. Neither he nor Sora had really had the energy to shave their heads since they’d left home. It felt weird. And _itchy_. But really, he didn’t care to go through that effort just yet, and they would need the extra warmth. He snapped his glider open, feeling the wind picking up, and launched himself into the moonlit sky.

Roxas whooped as he left the ship behind, circling higher and higher. Honestly, right now the air was about as cold as it was at the monastery, and without the constant sickening rocking of the ship, he could finally enjoy the sea-salt smell on the breeze.

Far below him, something flickered across the waves briefly, gleaming in the fading moonlight before vanishing. A moment later, it emerged again, and Roxas caught a brief glimpse of brightly-patterned scales.

A sea serpent? This far south? Roxas swooped closer to the water, curious.

There! Almost too close for comfort, a sleek, powerful head broke the surface of the water. Definitely a sea serpent, definitely too far south for it to be healthy…and definitely looking for something.

Roxas skimmed the water’s surface, trying to catch the serpent’s eye without getting close enough to potentially get eaten. Waves lapped at his toes and threatened to overbalance him and plunge him into the ocean, but Roxas was entirely fixated on the shimmering creature. Its eyes were golden, each as big as Roxas himself, and almost hypnotic.

“Why are you here?” Roxas asked quietly.

_‘For you, Avatar.’_

Roxas almost let go of his glider in shock. He hadn’t been expecting an actual _response_. “For me? …Why?”

 _‘You are in danger.’_ The sea serpent slowed its pace, swimming in large, lazy circles now. Roxas mimicked its path in the air, still unwilling to get too close.

“Danger?” He snorted. “Nobody even knows I’m the Avatar. They think it’s my twin brother.”

One golden eye rolled up in his direction and winked slowly at him. _‘You are unprotected and poorly trained. You, Avatar, are more vulnerable than you know.’_

A flush crept up Roxas’ face despite the chill. “Yeah, poorly trained. I know. You don’t have to rub it in.”

_‘Heed my warning, Avatar. This world needs you. Not all of us can afford to wait around for the next one to come of age, you know.’_

And with that cryptic statement, the serpent dove beneath the waves, leaving Roxas soaked, spluttering, and shivering.

“This is bison shit.” Roxas veered back towards the distant shadow of the ship, making a face. “Nobody cares about me. How am I supposed to be in danger?”

Sora was still dead asleep in their hammock by the time Roxas returned. The younger twin hurriedly blasted himself dry in the corridor before wrapping a spare blanket around himself and crawling back in with his brother. No point in catching a cold on top of everything else.


	3. Chapter Three

**Summary for the Chapter:**

> Still pondering the serpent's warning, Roxas continues his journey south...

If Sora noticed that Roxas was still damp the next morning, he didn’t mention it. He just dried off his half-asleep younger twin with the blanket and a fond chuckle before dragging him along to the upper deck.

Master Xaldin was waiting for them. The stiff breeze made his disapproving gaze at their lateness seem even colder. Honestly, Roxas was convinced Xaldin was creating the chilly wind himself purely for effect.

“You two should have been up at dawn.”

“Sorry, sorry, Master Xaldin, I just couldn’t wake up!” Sora was already chattering a mile a minute, any sign of sleepiness completely vanished in the bright morning sunlight. Roxas just yawned, settling into the first position of their morning practice forms in perfect synchronization with Sora. The good thing about getting up early to do this every day for years is that he could just let his muscle memory take over, so Roxas’ body could perform the tasks while his night-owl brain was still getting into gear.

“So, who’s going to be our waterbending teacher, Master Xaldin?” Sora asked as he and Roxas circled each other, the wind slowly whipping up around them. “I mean, uh, we…never got told anything about what to expect, except that it’s gonna be cold.”

“I believe the decision was to choose a master close to your own age.” Xaldin frowned, as if that fact didn’t sit well with him at all. “I know very little else other than his name is Demyx, and he is supposedly a brilliant waterbender. Whether he is a brilliant _teacher_ as well…that remains to be seen.”

Roxas and Sora shared an intrigued glance. A younger master could be a good thing; in their experience too many older masters were set in their ways, and they both learned much better with more flexible teachers.

“How much longer until we get there?” Roxas broke formation to face Xaldin directly, excited for the first time since they’d left home.

Xaldin’s mouth twisted ever so slightly at the question. “A few more days at the most. The weather is supposed to be clear until then, otherwise we’ll have to stop somewhere and wait, since we have no _trained_ waterbenders aboard to ease the way.”

Roxas didn’t miss the emphasis. “Too bad,” he said with a strained smile. “Hope the weather behaves then, huh?”

“Yes, we can only hope,” Xaldin responded flatly. “You’re dismissed, both of you. Obviously your minds are elsewhere this morning.”

Sora immediately grabbed Roxas’ hand, dragging him towards the stern of the ship.

“Sora, what—”

“I want to see. About the waterbending.”

The ship bounced on the waves, spraying them both with seawater. Sora barely paused to wipe it out his eyes, too busy scanning for crew members.

“Sora, I _can’t_ ,” Roxas protested faintly. He could barely make a ripple as it was, and half the time _that_ was because he’d accidentally airbent instead.

“That means you need to practice, then!”

Roxas’s tired blue eyes met Sora’s bright, energetic ones. He envied his brother’s energy.

“But—”

“Nope! No buts! We have nothing else to do today anyway, and you’re not gonna get seasick if you’re actually doing something, right?”

Just the thought of sitting around made Roxas turn green. “…Fine.”

Neither of them actually knew any waterbending forms, so they slipped back into their airbending warm-ups again, with Roxas shifting his focus to the ocean around them instead.

“Feel anything?” Sora asked, idly tossing a ball of air from one hand to the other.

“I…” Roxas frowned. “I think so?” There was definitely _something_ tugging at his senses. Not the usual currents of the wind around them. Something heavier. “Huh.”

Sora stopped moving, tilting his head curiously. “What is it?”

“You’re right.” Roxas managed a grin. He adjusted his stance, sweating a little from the strain. “It _is_ a lot like air. But it won’t… _move_ …”

Roxas stumbled as a wave of dizziness washed over him. The connection to the water, already tenuous, snapped completely.

“Roxas!”

Sora crossed the distance between them in an instant, catching his brother before he hit the deck. “Roxas, are you okay?” he asked breathlessly, swiping his fingers over Roxas’ ashen forehead. Roxas was clammy, his breathing labored.

“I had it,” Roxas mumbled faintly. “Sora, I…know I had it.”

“You did, I’m sure you did. C’mon, Roxas, stay awake, we have to get to Master Xaldin…” Sora had never seen Roxas so pale. What exactly had _happened_? And how was he going to explain this?

“ _No_.” Roxas grabbed Sora’s wrist. “We’re…not telling him.”

Slowly, agonizingly slowly, Roxas’ breathing steadied. His skin was still terribly cold to the touch.

“Sora…?”

“I’m here.” Sora realized he was shaking and took a deep breath to re-center himself. He had to stay calm. “Roxas?”

There was a short silence as Roxas concentrated, taking inventory. “…I can stand.”

“You sure about that?”

Roxas nodded tightly.

The two of them carefully made their way back to the lower deck and their hammock. Roxas was at least regaining some color in his cheeks, though he still needed Sora’s support to walk. Once they’d gotten back to their cabin and Roxas was lying down, Sora headed back for the door.

“I’m gonna get some food. See if they have any fruit left.”

Roxas nodded with a faint laugh. “I’ll be here.”

Sora leaned in to kiss his brother’s forehead. “I promise I won’t be long.”

Roxas wrapped himself tighter in the blankets as Sora shut the door quietly behind him, fighting down a wave of nausea. The motion of the sea seemed even more intense now, somehow.

He failed to notice the shadow lurking in the frame of the porthole, watching him.


End file.
